In Kant’s moral theory, we do not have duties to animals, though we have duties with regard to them. I reconstruct Kant’s arguments for several types of duties with regard to animals and show that Kant’s theory imposes far more robust requirements on our treatment of animals than one would expect. Kant’s duties regarding animals are perfect and imperfect; they are primarily but not exclusively duties to oneself; and they condemn not merely cruelty to animals for its own sake, but also, such things as killing them for food when our health does not require it and ingratitude to service animals. Central to understanding these duties is appreciating Kant’s concern for our morally useful emotions, for it is primarily because of the effect that cruelty to animals has on our sympathetic emotions—which greatly help us treat other rational beings appropriately—that we have duties not to be cruel to animals. Yet cruelty and callousness toward animals are not problematic only because they may weaken some of our morally useful emotions. Cruelty and callousness toward animals are problematic also because they oppose our morally useful emotions; these emotions, as part of the perfection of our nature, should be honored, supported, and furthered, unless there are compelling reasons not to do so in particular cases